<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>ajsp页面</title>
</head>
<body>
    <%
      Object user = session.getAttribute("user");
      //判断用户是否为空
      if(user == null){
        request.getRequestDispatcher("/login.jsp").forward(request,response);
        return ;
      }
    %>
    a.jsp
</body>
</html>